People with dyslexia, who ordinarily struggle to read, sometimes remark that reading is easier when e-readers are used. Here, we used eye tracking to observe high school students with dyslexia as they read using these devices. Among the factors investigated, we found that reading using a small device resulted in substantial benefits, improving reading speeds by 27%, reducing the number of fixations by 11%, and importantly, reducing the number of regressive saccades by more than a factor of 2, with no cost to comprehension. Given that an expected trade-off between horizontal and vertical regression was not observed when line lengths were altered, we speculate that these effects occur because sluggish attention spreads perception to the left as the gaze shifts during reading. Short lines eliminate crowded text to the left, reducing regression. The effects of attention modulation by the hand, and of increased letter spacing to reduce crowding, were also found to modulate the oculomotor dynamics in reading, but whether these factors resulted in benefits or costs depended on characteristics, such as visual attention span, that varied within our sample. People with dyslexia, who ordinarily struggle to read, sometimes remark that reading is easier when e-readers are used. Here, we used eye tracking to observe high school students with dyslexia as they read using these devices. Among the factors investigated, we found that reading using a small device resulted in substantial benefits, improving reading speeds by 27%, reducing the number of fixations by 11%, and importantly, reducing the number of regressive saccades by more than a factor of 2, with no cost to comprehension. Given that an estimated 5% to 17% of all people struggle with the system of reading currently in place [1] , it is reasonable to ask whether this evolution in reading can lead to new methods that are better matched to the atypical neurology of those with dyslexia and thus might ameliorate its detrimental effects. Anecdotally, people with dyslexia sometimes remark that reading on e-readers seems easier, and researchers have long suspected that altered treatments of text may produce beneficial effects in those who struggle to read. In this paper, we use eye tracking to observe high school students with dyslexia as they read using popular handheld portable reading devices. Our experiment varies a number of factors that differentiate such devices from traditional presentations of text. It investigates the effects of the device being held in the hand, of differing linewidths (which result from devices of different sizes), and of the alteration of inter-letter spacing. Stimuli Participants read material excerpted from an age-appropriate non-fiction book on biomedical science [22] . Passages consisted of 208 words and were randomly selected from the book, avoiding segments containing unusual formatting or extensive dialogue. Each passage began at the start of a sentence, and ended after 208 words, appending the word “END.” Sixteen such passages were selected, in addition to one reserved for practice. All text was formatted using a 32-pt Georgia font, with a line spacing that was increased by a factor of 1.7 compared with normal spacing. In the POD condition, reading the entire 208-word passage required 12 such page turns, while the PAD condition required only one. Participants read all text silently. When reading of the entire 208-word passage was completed, participants were asked to recall the content of the passage read, and their description was rated for fidelity (FIDELITY), coding for the number of substantive details recalled using a four-point scale (0–3). A score of zero indicated the participant was unable to recall any details, while a score of three indicated three or more details were described. Similarly, when participants approached the end of a page, procedures required them to engage in special actions (e.g., to gaze at the page-turn target) that could potentially disrupt their reading. For this reason, the automated estimates of when the last word is read were also considered unreliable. To counteract such effects, we based the measurements we report on parameters observed over a “trimmed” reading interval that ignores a fixed span of text at the start and end of each page. Degree of Reading Power (DRP) scores for each student, an a priori measure of their overall reading level, was used to create a dummy variable (High Reading) used to divide participants into high and low reading level groups. Those with high reading levels read well with either spaced or normal text, however, those most impaired read more effectively in the spaced condition. (Error bars indicate +/−1 s.e.) 10.1371/journal.pone.0071161.t005 Table 5 Fidelity as dependent variable. If anything, students read more slowly when text was spaced ( Fig. 7 ). While spacing made little difference to those with high VAS scores, those with low VAS scores read faster when text was normally spaced. The only benefit of letter spacing we observe is that the number of downward errors (inappropriate glances down to text below the line currently read) is decreased. However, given only about one percent of all fixations are downward errors (see Table 2 ), this effect is of negligible importance in our study. We speculate that the reason our study only partially reproduced findings of [14] is that the nature of the format manipulation differed in the two studies. And referring to Table 3 , the incidence of horizontal regression is (LEFT/FIX) is 19% for PAD, and 9% for POD, a ratio roughly proportional to the probability determined by linewidth. Thus, indeed, the incidence of horizontal regression appears to roughly scale with the linewidth, as expected. However, another consequence of breaking the text into short lines is that, when formats are narrowed, opportunities for re-inspection across line boundaries increase.